Microsoft is prototyping its own wrist-worn device. A reliable source familiar with Microsoft's Xbox plans has revealed to The Verge that the company has been developing a wrist-worn device for just over a year. We understand that Microsoft had originally planned to release a "Joule" heart rate monitor accessory for the Xbox, but the company has since decided to focus on a smartwatch instead. The Wall Street Journalfirst reported on Microsoft's plans earlier this week, citing unnamed supply chain sources who claim Microsoft has requested 1.5-inch displays from component manufacturers.

Microsoft's smartwatch is said to be in the prototype phase, with teams who have worked on Xbox accessories and the Kinect sensor focused on the device. We're told it features removable bands attached to a 1.5-inch touch display. One prototype includes the same magnetic power connector that Microsoft uses on its Surface tablets. The MagSafe-like connector is made up of five pins and can transmit both power and data, but we're told this is only a prototype and a final design may omit the connector.

Microsoft previously fielded a range of smartwatches back in 2004 under the SPOT brand. The devices used FM radio signals to obtain news, weather forecasts, and stock information. Microsoft discontinued the devices in 2008, shuttering the service fully last year. Microsoft's Bill Buxton recently outlined the 37-year history of smartwatches at a talk during the company's TechFest research event. At the time, we speculated Microsoft may re-enter a market it tried to kickstart years ago, and it looks like that may soon be a reality.